US2648985A

US2648985A - Hoisting and stretching apparatus

Info

Publication number: US2648985A
Application number: US252566A
Authority: US
Inventors: Louis V Mallory
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-10-22
Filing date: 1951-10-22
Publication date: 1953-08-18
Anticipated expiration: 1970-08-18

Description

VI .llllillll Aug. 18, 1953 v. MALLORY HOISTING AND STRETCHING APPARATUS Filed 001;. 22, 1951 Patented Aug. 18, 1953 UNITED STATES TENT OFFICE HOISTING AND STRETCHING APPARATUS Louis V. Mallory, Rock Island, 111.

Application October 22, 1951, Serial No. 252,566

11 Claims. 1

My invention relates to an improvement upon the hoisting apparatus covered by Letters Patent of the United States, No. 2,564,541, issued upon my application on August 14, 1951. Since filing that application, I have improved my invention to give the jack a better controlled releasing feature, by letting the jack with its load down in a position step-by-step manner, rather than leaving it to be released by the skill of the operators. Some operators cannot seem to grasp the idea. of just applying pressure enough to the handle to allow the lower clutch block to slowly slide down the post, but grab the handle like a pump handle and shove down too hard which results in a chattering jerky descent that might be injurious to the bumper brackets of the automobile on which used.

In order to give the jack this control feature, I have invented an interlocking assembly of releasing members or straps that are slidably mounted on the clutch blocks of the jack in such a manner that the release of the clutch elements is effected alternately, when the lever is swung to the full-length of stroke available.

The objects of my invention are to provide simple, convenient means for releasing hoisting apparatus by successive steps thereby preventing heavy shocks that would occur if the apparatus is entirely released all at once. Other objects will appear from the specification.

I accomplish these objects by the means illustrated in the accompanying drawings, in which,

Figure 1 is a front elevation of my apparatus;

Figure 2 is a side elevation partly in section on the line 22 of Figure 1, showing both clutch blocks in gripping position against downward movement but free to allow upward movement thereof;

. Figure 3 is a sectional detail showing the upper clutch block in gripping position andthe lower block in free position for downward movement;

Figure 4 is a top or plan view;

Figure 5 is a sectional detail on the line 55 of Figure 2, but omits the plunger I5 for clearness.

bar I is inserted in a socket 2.I united to or formed integral with a base 2 which may be of any suitable size, shape and material, iron or steel being preferred.

5 Upon the bar I an upper clutch block 3 and a lower clutch block 4 are slidably mounted. The

upper block 3 has ivotally mounted thereon a forked handle 5 carried by a pivot pin 6. The shorter end of the handle 5 is secured by a pivot 13 to the upper end of links I, the lower ends of which are pivotally mounted upon the block 4.

Bores 3.I and 4.I are formed in the blocks 3 and s respectively and extend obliquely upwardly therein with their inner ends adjacent the bar I.

Steel balls it and I I are seated in the bores 3.I and M and compression springs I2 and I3 are mounted in the bores to bear against the balls tending to drive them toward the inner ends of the bores and into contact with the bar I. The outer end of the spring I2 bears against the pivot 6 and the outer end of the spring I3 is retained in the bore by a plug I4.

Plungers I5 and I6 are slidably mounted in the blocks 3 and e in suitable bores in the upper part thereof. The inner ends of the plungers are arranged to contact the balls I0 and I I.

A slide II consisting of a flat strip or bar of metal, is mounted upon the block 3 and secured by an annular spring I8 which is adjustably held by a thumb screw I9.

The upper end of the slide [1 has an inwardly extending finger or flange 20 formed thereon which is arranged to contact the upper end of the plunger I5 when approaching contact with the top of the block 3 and to release it when moved away from the block 3. The lower end of the slide IT has an upturned lug 22 formed thereon which extends through an opening 24 in the outer fold of the strip 23 in position to. contact the upper end of said fold as the block 3 rises a certain distance.

The body of the slide I? has an opening 2I formed therein through which the thumb screw 9 passes and which is larger than the thumb screw so as to permit limited up and down movement of the slide IT relative to the block 3.

The slide 23 comprises a fiat strip of metal folded upon itself at the lower end and secured to the block a by an annular spring 25 mounted upon the outer fold of the slide 23 and secured by a thumb screw 25 to the block 4. The thumb screw 26 is threaded into the block 4 and passes through an opening 27 in the slide 23 whereby the slide is free to move up and down within certain limits.

The inner fold of the slide 23 has a finger or flange 28 formed thereon arranged to extend over the plunger i6 and contact the plunger when approaching the block 5 whereby the ball II may be forced along the bore M and out of contact with the bar I.

In like manner, the plunger I5 when pushed inwardly by the finger or flange 29, will contact the ball lfi and force it along the bore 3.l and out of contact with the bar I.

The slides ii and 23 are so proportioned that as the handle 25 is raised upward the full length of its stroke, it will raise the block 3 and the slide I! so that the lug 22 will contact the upper part of slide 25 and raise it whereby the flange 28 will clear the plunger it and allow the spring I3 to force the ball into contact with the bar. i. When in that position, the block 4 and ball II will secure the block 4 in stationary position upon the bar 5. handle is continued the upper part of the slide 23 will hold the lug 22 andslidellagainst further upward motion and the flange-of the slide 3 into contact with the flange 28 and cause the flange 25 to contact the plunger is and-thereby push the ball I 5 out of contact with'the bar 1 and allow the block t to descend as far as the links I will permit.

The bores in the slides and the thumb screws are so proportioned that the handle can be operated through about one-half of its total possible travel in either direction without causing the lug 22 to contact the upper partof the slide 23 or to cause the flange 28 to contact the plunger! 6 and it is only when the handle is given a full stroke in either direction that the

flanges

26 and 28 Will act upon the plungers l5 and i6. Thus the hoist may be used to raise any object contacted by the hook 28.! of the block ll by intermediate strokes of the handle through the middle portion of its possible travel, and to lower it step-by-step in full-length strokes of the handle.

When it is desired to lower the load carried by the hook 23.5, the handle will be given full length strokes and as one of the blocks 3 or is released thereby, the other one will be held in place and in this way the load can be lowered stepby step to the bottom of its travel and the jerksavoided which would be caused by a longer drop'of the weight.

In order to provide detents to stabilize the slides H and 23 when holding the plungers, I

form small bores in the upper part of'each r block 3 and i with helical compression springs;

by-step descent, while an intermediate manipulation of lever 5 results in a step-by-step upward action of the blocks 3 and 4 and hook 233.!

The upper end of the rod i may be provided with a hook 33 whereby the bar may be suspended or anchored by a chain or rope instead of resting upon the base 2.

Various modifications may be made in the form and proportions of various parts without departing from the spirit of my invention as expressed in the claims and I do not limit my claims to the precise forms shown in the drawings.

I claim:

1. In a hoisting jack of the class described, a supporting bar, a pair of clutch blocks lidably When the upward movement of the- Then when the handle is swung I downwardly full distance, it will carry'the'block mounted thereon, a manually operable handle pivotally connected to said blocks and arranged to exert pressure thereon in opposite directions simultaneously, an oblique bore formed in each block and a ball mounted in each bore springheld in contact with the bar, plungers slidably mounted in the blocks with their inner ends arranged to contact the balls and move them out of contact with the bar when depressed, coacting stripsoperable by the handlein either direction slidably mounted on each block and having inturned flanges in position to actuate the plungers, and means whereby intermediate stroke of the handle in the middle portion of its possible travel will advance the blocks in alternation while full length strokes of the handle Will cause the blocks to retreat in alternation.

2. In a hoisting jack of the class described, a supporting bar, a pair of clutch blocks slidably mounted thereon, a manually operable handle pivotally connected to said blocks and arranged to exert pressure thereon in opposite directions simultaneously, an oblique bore formed in" each block and a ball mounted in each bore springheld in'contact with the bar, plungers slidably mounted in the blocks with their inner ends arranged to contact the balls andmove them out of contact with the bar when depressed, coacting strips slidably mounted on each block having inturned flanges in position to actuate the plungers, and means whereby repeated full strokes of the handle will cause the plungers to carry the balls out of contact with the bar in alternation and thereby allow retreat of the blocks in alternation.

3. A hoisting jack as described in claim and means whereby short strokes'of the handle in the middle of its course of travel will not move the balls out of contact with the bar simultaneously but will cause the blocks to advance in alternation.

4. In a hoisting jack of the class described, a supporting bar, a pair of clutch blocks slidably mounted thereon, a reciprocating manually operable handle pivotally connected to said blocks and arranged to exert pressure thereon in opposite directions simultaneously when moved in either direction, a pair of clutch blocks slidably mounted on the bar having an angular bore formed in each block and a ball mounted in each bore spring-held in contact with the bar, a plunger slidably mounted ineach block with its inner end arranged to contact the ball and roll it along its bore and out of contact with the bar when plungers are depressed, and coacting means movably mounted on each block arranged to contact and actuate the plungers in alternation upon the handle being reciprocated through the full length of its possible stroke.

5. A hoisting jack as described in claim 4, said means being also arranged toavoid actuating the plungers when moved only through the middle portion of its possible travel.

6. Ina hoisting jack of the class described, a supporting bar, a pair of clutch blocks slidably mounted thereon, a reciprocating manually operable handle pivotally connected to said blocks and arranged to exert pressure thereon in opposite directions simultaneously when moved in either direction, a pair of clutch blocks slidably mounted on the bar having an angular bore formed in each black and a ball mounted in each bore springalong its bore and out of contact with the bar when the plungers are depressed, strip slides mounted upon the clutch blocks respectively arranged to contact the plungers and move them downwardly, a pair of bores in each of the clutch blocks at right angles to the supporting bar, with balls movably mounted therein a compression spring seated in each of such bores to exert pressure outwardly against the balls, and smaller bores or indentations formed in the slides arranged to permit the balls to enter therein a short distance whereby the balls may detain the slides against accidental movement along the blocks.

'7. In a hoisting jack as described in claim 6, means whereby the balls may be forced out of the slides bores in alternation by full movement of the handle in reverse directions.

8. A hoisting jack as described in claim 4, said means including small bores in each of the clutch 1 blocks with balls movably mounted therein and compression springs seated in the bores arranged to exert pressure outwardly against the balls, small bores 0r indentations formed in the slides arranged to permit such balls to enter therein a arranged to engage the bore in the strip when 1 the bores in the block and strip are in alignment.

10. In a hoisting jack having a supporting bar, clutch blocks slidably mounted thereon, metal strips slidably secured on said blocks by resilient means, transverse bores formed in said blocks, slightly smaller bores in said strips, and springheld balls movably mounted in the transverse bores arranged to engage the bores in the strips when the bores in the blocks and strips are in alignment.

11. In a hoisting jack having a pair of clutch blocks slidably mounted on a support, locking means to lock the clutch blocks against descent, means mounted in said blocks to detain them normally against accidental movement, including transverse bores formed therein, and helical springs mounted in the bores arranged to exert pressure against balls mounted in said bores and cause the balls to engage corresponding bores or indentations in adjacent metal strips slidably mounted on the clutch blocks and arranged to release said locking means by manual movement of a handle pivotally mounted on the clutch blocks.

LOUIS V. MALLORY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 383,709 Crecelius May 29, 1888 1,026,347 Foor May 14, 1912 1,174,363 Starr Mar. 7, 1916 1,874,128 Seeber Aug. 30, 1932 2,196,263 Johnston Apr. 9, 1940 2,573,877 Schweitzer Nov. '6, 1951 2,583,544 Burdick Jan. 29, 1952 2,597,691 Wikstrom May 2 0, 1952